Wreckage was found the following day off the coast of Co Antrim at Glenarm but, as yet, the men have not been located.

The Police Service of Northern Ireland released a statement in which the families expressed thanks to the search teams.

"The families of two men who have been missing since a small fixed wing aircraft went missing on Thursday, 9 June would like to express their thanks to all agencies and in particular all the volunteers who have given up their time to search for their loved ones," said a PSNI spokesman.

Inspector Michael McDonnell detailed the search efforts to date.

"During this search operation Police have been supported in their efforts by the work of Community Rescue Service, Maritime and Coastguard Agency, RNLI, Northern Ireland Environment agency and North West Mountain Rescue," he said.

"State of the art sonar equipment and seabed scanning equipment has also been deployed, to ensure that appropriate technical expertise is being utilised to maximise the effectiveness of the overall operation.

"The PSNI helicopter has also conducted over-flights of the harbour and further out to sea. A series of boats and vessels have also been involved in the search on the water.

"The Community Rescue Service team will continue in their search of the area and they along with police will continue to respond to any sightings reported.

"I would like to thank all agencies concerned for their continued support. Over the coming days we will continue to work with search and rescue teams, when called upon. I would also ask the public to be vigilant if they are near Glenarm Harbour and coastlines.

"Anyone who notices anything unusual is asked to contact police on the non-emergency number 101."

Mr McDonnell said the families of the missing men had requested privacy.